Gravity with Brian Cox

PC_Dave

That video clip is brilliant! My tiny, under powered brain nearly exploded trying to comprehend it all! 

skunkwerx

Gravity... it always gets me down.

vale

Nitefly said:

Brilliant!

I didn't get the last bit though, where he was on about Einstein, saying that they weren't moving at all?  It bloody looked like they were!

it's about frame of reference.

if you are in a lift and the cable breaks...

viewed on cctv footage within the lift you are not moving down at all, you are stationary standing on the floor of the lift.

but someone standing outside the building wearing x-ray glasses would see you 'falling' (moving towards) towards the floor of the building.

if you pull back even more, viewed from space, a viewer would see you moving towards (being attracted to) the earth a lot, but also the earth moving very slightly towards (being attracted to) you.

that is what he means by there is no 'falling' involved. it's just two masses being attracted to each other.

the amount each mass moves towards the other dependent on the ratio of the relative masses of the two objects.

vale

ps. at the sub-atomic level the masses are so small that gravity isn't really a feature.

de Broglie wavefunctions are what i'm trying to make sense of at the moment. total crazy fun!

1m30s to 2m30s: "you're everywhere in the universe... but not very much."

vale

ICBM said:

The Weak Anthropic Principle.

ie it's only in a universe (and in a part of it) capable of supporting life, that life will be able to evolve and understand that it does, AKA a self-fulfilling condition of our existence.

it's curious when people say 'isn't it strange (or 'miraculous') that life evolved?'

given our universe,

with all the matter that exists in it (created at the moment of the big bang),

inevitably subject to the four forces (gravity, electromagnetism, strong/weak nuclear) that were also created at the time of the big bang (originally one superforce that split into four almost immediately after),

all interacting upon each other, nanosecond after nanosecond, over all the time that has passed since (13.7b years),
 
it would actually be infinitely more strange or 'miraculous' if something didn't evolve.

HAL9000

The video at the top of this thread is amazing. Even though we all learnt that gravity affects all objects in the same way, seeing it actually happen just looks so counter-intuitive.

ICBM

vale said:

it's curious when people say 'isn't it strange (or 'miraculous') that life evolved?'

given our universe,

with all the matter that exists in it (created at the moment of the big bang),

inevitably subject to the four forces (gravity, electromagnetism, strong/weak nuclear) that were also created at the time of the big bang (originally one superforce that split into four almost immediately after),

all interacting upon each other, nanosecond after nanosecond, over all the time that has passed since (13.7b years),
 
it would actually be infinitely more strange or 'miraculous' if something didn't evolve.

I’m not so sure about that. The chance of self-replicating life coming into existence is extremely small, even given perfect conditions - as far as is known, it has only ever occurred once on Earth... every known living thing is descended from the same single original lifeform. (Because there are two mirror-image forms of DNA. If the origin of life was common, you would expect a multitude of 'family trees' of life, some with each form of DNA. But there is only one.) The evolution of multi-cellular life is another huge hurdle - it seems as if primitive life was present on Earth for billions of years before that happened. Given both those things, it's then probably a certainty that intelligent life would eventually evolve, but those seem to be incredibly unlikely events in the first place.

There's also the Fermi Paradox, which would seem to imply that we're either alone as an intelligent species in our galaxy, or at best the first. The Drake equation sets out to formulate it, and although it's easy to get results in the large positive numbers if you make certain assumptions, if you only change a few orders of magnitude in the origin of life factors, it can rapidly become less than 1. And although there are hundreds of billions of galaxies, whether that means there are other intelligent species in the universe really depends on the ratio of two extremely large numbers, neither of which is known even approximately.

The universe is not even that big or that old, in the sort of statistical terms you would need to make a 'monkeys and typewriters' assumption that it *must* have occurred somewhere in it. It's possible to calculate the total number of quantum events that can have occurred since the Big Bang, and although by human standards it's unimaginably large, in mathematical terms it's really not. It's actually quite a bit smaller than the number of possible combinations in just two packs of playing cards.

ICBM

HAL9000 said:

The video at the top of this thread is amazing. Even though we all learnt that gravity affects all objects in the same way, seeing it actually happen just looks so counter-intuitive.

It's a bit like watching the dust kicked up by the astronauts on the Moon - it travels in simple ballistic arcs, and does not float.

Explain that one, conspiracy nuts...

menamestom

It’s amazing to see things like this, even though we know that’s how it works.  Also a reminder into the engineering, effort and passion scientists go to to prove and advance existing theories.

I don’t see flat earthers or gravity deniers making any effort to offer scientific alternatives or using their time and resource to test their own theories.  In an age where it’s ‘my conclusion is better than yours’ clips like this serve as a great reminder that it doesn’t work like that, and demonstrating a simple thing like the removal of air resistance can take monumental amounts of time and resource.

Jalapeno

Is it better than John Mayer's Gravity ?

Danny1969

menamestom said:

It’s amazing to see things like this, even though we know that’s how it works.  Also a reminder into the engineering, effort and passion scientists go to to prove and advance existing theories.

I don’t see flat earthers or gravity deniers making any effort to offer scientific alternatives or using their time and resource to test their own theories.  In an age where it’s ‘my conclusion is better than yours’ clips like this serve as a great reminder that it doesn’t work like that, and demonstrating a simple thing like the removal of air resistance can take monumental amounts of time and resource.

The thing as I understand it we don't understand how gravity works .... not really. Or if we do we don't understand how matter works. Newtons law is simple enough and got us to the moon and back but he was never happy with his own explanation of gravity. Einstein's improved on it in terms of effects and consequences but the fundamental problem is to make our theories about gravity work with what we can observe in the universe we have to invent an invisible force to account for the amount of gravity .... dark matter is the current theory but that's all it is at this point. 
Really interesting stuff though 

axisus

It's a little known fact but Brian Cox was going to compete at the olympics, until someone realised that his inclusion in the Coxless fours rowing team would cause a rift in the time space continuum.

Emp_Fab

I want to make love with a super-brainy female astro-physicist.  Nothing is sexier than a highly intelligent woman.

RMJ

Intelligent thread is too intelligent

57Deluxe

OP title sounds like it should be about Brian's balls dropping...

LBS - Long Ball Syndrome.

vale

ICBM said:

vale said:

it's curious when people say 'isn't it strange (or 'miraculous') that life evolved?'

given our universe,

with all the matter that exists in it (created at the moment of the big bang),

inevitably subject to the four forces (gravity, electromagnetism, strong/weak nuclear) that were also created at the time of the big bang (originally one superforce that split into four almost immediately after),

all interacting upon each other, nanosecond after nanosecond, over all the time that has passed since (13.7b years),
 
it would actually be infinitely more strange or 'miraculous' if something didn't evolve.

I’m not so sure about that. The chance of self-replicating life coming into existence is extremely small, even given perfect conditions - as far as is known, it has only ever occurred once on Earth... every known living thing is descended from the same single original lifeform. (Because there are two mirror-image forms of DNA. If the origin of life was common, you would expect a multitude of 'family trees' of life, some with each form of DNA. But there is only one.) The evolution of multi-cellular life is another huge hurdle - it seems as if primitive life was present on Earth for billions of years before that happened. Given both those things, it's then probably a certainty that intelligent life would eventually evolve, but those seem to be incredibly unlikely events in the first place.

There's also the Fermi Paradox, which would seem to imply that we're either alone as an intelligent species in our galaxy, or at best the first. The Drake equation sets out to formulate it, and although it's easy to get results in the large positive numbers if you make certain assumptions, if you only change a few orders of magnitude in the origin of life factors, it can rapidly become less than 1. And although there are hundreds of billions of galaxies, whether that means there are other intelligent species in the universe really depends on the ratio of two extremely large numbers, neither of which is known even approximately.

The universe is not even that big or that old, in the sort of statistical terms you would need to make a 'monkeys and typewriters' assumption that it *must* have occurred somewhere in it. It's possible to calculate the total number of quantum events that can have occurred since the Big Bang, and although by human standards it's unimaginably large, in mathematical terms it's really not. It's actually quite a bit smaller than the number of possible combinations in just two packs of playing cards.

"The chance of self-replicating life coming into existence is extremely small, even given perfect conditions - as far as is known, it has only ever occurred once on Earth."

to be fair, that's like never having left the house & claiming to be the only person in the street you know to have a goldfish. we've hardly gone anywhere yet.

"every known living thing is descended from the same single original lifeform"

because LUCA ate or out-evolved everything else & monopolised territory & resources.
think of all the CO2 atmosphere favouring life-forms that vanished during the great oxygenation event. a whole branch of evolutionary potential hacked off before it got started.
if that event had not occured would we be talking about the same LUCA?

the trouble is when you get down to the level or archea & bacteria & extremophiles in general, they leave little if anything in the fossil record. like searching for a discarded fruit gum in a volcano. proterozoic earth was a jelly world. & before that a few tenuous clusters of molecules.
recent discovery of carbon12 isotopes in archean rock (a few sites now) look promising as far as catching a fleeting glimpse of that world though. i'm pretty excited about that.

"The evolution of multi-cellular life is another huge hurdle - it seems as if primitive life was present on Earth for billions of years before that happened. Given both those things, it's then probably a certainty that intelligent life would eventually evolve, but those seem to be incredibly unlikely events in the first place."

that's being unpicked. agree that self-replicating is the biggie. RNA world looks interesting but nothing conclusive yet. not the only one but most developed so far. TCA cycle another.

the rest is kind of dealt with, to a greater or lesser extent;
prebiotic soup easy. miller & urey etc.
selecting/organising molecules (including selecting for chirality) suited to 'sparking' life ; heat, ph, uv, mineral surfaces.
& once you have that (so far elusive) self-replicating system, those same selecting/organising environments become selective pressures in the darwinian sense.
so you get evolution free with self-replicating systems that are able to mutate/adapt.

so i'm in the strong anthropic principle camp. but respect & consider all angles & arguments.

"the origin of life & evolution were necessary because of conditions on earth & the existing properties of the elements" (Ernest Schoffeniels).

ICBM

It’s highly unlikely that if life developed independently at multiple locations or times on Earth, that there would now be only one surviving ‘tree’. This is the key to it in my opinion - if even one lifeform not related to all the others can be discovered on Earth, it makes the probability of life elsewhere a near certainty. Until it is, the probability remains near zero.

It also doesn’t answer the Fermi Paradox, but we could simply be the first - the universe is not that old yet. The conditions necessary to create complex life can’t have occurred much before the formation of the Earth due to the time it takes to form the heavier elements in high enough proportions via star formation and destruction.

Time also matters in another way - it was around 4 billion years between the formation of the Earth and the evolution of complex life. The remaining lifespan of the Sun as a stable star is around 5 billion years - to us, unimaginably vast, but the two numbers are similar enough that it’s quite possible that even on planets which achieve primitive life, almost all of them simply run out of time.

I prefer the weak anthropic principle to the strong one, but either of them are compatible with us being the only intelligent life in the universe.

vale

ICBM said:

I prefer the weak anthropic principle to the strong one, but either of them are compatible with us being the only intelligent life in the universe.

oh i don't think we're alone, but it could be either/or, & the exciting thing is it's still wide open & anything could happen anyday to change everything.
i'm continually excited by it & constantly inspired to learn more.

on a tangent, that is why thing like the slug thread (also in off topic) makes me feel sad. on that i'm very much with whoever it was there who said they collect snails & take them out to the country to release them, rather than kill (i forget the commenter's name but i gave them a wiz).

on earth slugs are treated by many as a loathsome pest to be got rid of, but on any other planet in our solar system (or according to your inclination, the universe) they would be considered the most sophisticated known life-form. the very kings & queens of all evolution!

there's tragic perspective for you.

ICBM

vale said:

on a tangent, that is why thing like the slug thread (also in off topic) makes me feel sad. on that i'm very much with whoever it was there who said they collect snails & take them out to the country to release them, rather than kill (i forget the commenter's name but i gave them a wiz).

on earth slugs are treated by many as a loathsome pest to be got rid of, but on any other planet in our solar system (or according to your inclination, the universe) they would be considered the most sophisticated known life-form. the very kings & queens of all evolution!

there's tragic perspective for you.

In fact in cosmic terms it isn't very long since that would have been true on Earth. So if there is other intelligent life and they are capable of getting themselves here, perhaps they will think of us as slugs... in which case it would actually be better to be alone.

“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” - Arthur C. Clarke

Kilgore

I think there is plenty of alien life out there, some of it in refrigerated units in an Area 51 warehouse.